1. Field of the Invention
This invention relates to a socket for connecting two pipe ends by injection of adhesive into two annular spaces formed between the outer face of the pipe ends and the inner face of the socket. The tubular shell of the socket has a projection which extends radially inwards from its inner face and of which the side faces form a stop for the end faces of the pipe ends. The annular elements provided as centering and sealing rings have a face directed radially inwards to bear against the end faces of the shell and an axially extending face designed to bear against one of the faces of the shell. An annular flange is arranged on each side of the projection, surrounds the inner face of the shell and is designed for the sealing and centered insertion of the pipe ends. The shell, the rings and the annular flanges are made by injection molding.
2. Discussion of Related Art
One such socket is known from DE 31 09 422 A1. For connection, the pipe ends are pushed from opposite sides into the shell of the socket until they encounter the projection which extends around the inner face of the shell and acts as a stop and the annular elements provided as centering and sealing rings are clamped fast between the shell and the outer face of the pipe ends at the ends of the shell. Adhesive is injected through one or more injection openings into the annular space formed between the outer face of the pipe ends and the inner face of the socket, so that a gas-tight and water-tight connection is established between the pipes.
In some cases, the plastic pipes to be connected are distorted through prolonged storage and the effects of heat and are oval rather than round. In addition, the wall thicknesses and external diameters of the pipes vary. In order nevertheless to obtain an encircling annular space of sufficient thickness at each point of the circumference for safe injection bonding, the rings to be attached to the ends of the shell are provided. The annular flange extending around the inner face of the socket on each side of the projection is provided for the same purpose. In addition, the rings and the annular flanges are intended to prevent the escape of adhesive.
The socket is made of plastic by injection molding. Large numbers can only be economically produced when as few projections or recesses as possible are provided. However, the shell of the known socket with the encircling annular flange is made in one piece and the height of the projection forming the annular flange is relatively small so that problems arise during the injection molding of the shell.